The present invention relates generally to pumps, and more particularly to sliding-vane pumps.
It is known to provide sliding-vane pumps of the type wherein the actual pump forms a unit with the electromotor which drives it. In such constructions the housing of the pump has the output shaft of the electromotor extending into it in cantilever fashion, and the rotor of the pump is mounted on the output shaft for rotation therewith. The connection between shaft and rotor is by means of a key or the like. Such pumps can be of very compact construction, which is an advantage, as are certain other features of pumps of this type. However, this type of construction also has a significant disadvantage, namely the necessity of manufacturing all parts to very high tolerances. The effectiveness of a sliding-vane pump is primarily governed by the gap which develops between the outer rotor surface and the inner surface bounding the rotor cavity. The smaller this gap, the better will be the effectiveness of the pump. From this it follows that in order to maintain the gap as small as possible, very precise manufacturing tolerances must be maintained in the manufacture and assembly of the various components, and in particular with respect to the mounting of the rotor in the housing. This is particularly difficult to achieve when the rotor is mounted directly on the shaft of the electromotor, as in the particular type of construction here under discussion.